JPQL:状态字段路径无法解析为有效类型 [英] JPQL: The state field path cannot be resolved to a valid type

问题描述

我无法使该查询生效:

Query query = eManager.createQuery("select c FROM News c WHERE c.NEWSID = :id",News.class);
        return (News)query.setParameter("id", newsId).getSingleResult();

我得到了这个例外:

Exception Description: Problem compiling [select c FROM News c WHERE c.NEWSID = :id]. 
[27, 35] The state field path 'c.NEWSID' cannot be resolved to a valid type.] with root cause
Local Exception Stack: 
Exception [EclipseLink-0] (Eclipse Persistence Services - 2.5.0.v20130507-3faac2b): org.eclipse.persistence.exceptions.JPQLException
Exception Description: Problem compiling [select c FROM News c WHERE c.NEWSID = :id]. 

为什么会发生? :id和命名参数相同

Why does it happen? :id and named parameter are identical

我的实体课

@Entity
@Table(name="NEWS")
public class News implements Serializable{

    @Id 
    @SequenceGenerator(name = "news_seq_gen", sequenceName = "news_seq")
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "news_seq_gen")
    private int newsId;
    private String newsTitle;
    private String newsBrief;
    private String newsContent;
    private Date newsDate;
    @Transient
    private boolean selected=false;

//constructor and getters and setters 

推荐答案

之所以会发生这种情况，是因为News实体没有名为NEWSID的持久属性.持久属性的名称在JPQL查询中区分大小写，并且应使用与实体中出现的大小写完全相同的大小写形式.

That happens because News entity does not have persistent attribute named NEWSID. Names of the persistent attributes are case sensitive in JPQL queries and those should be written with exactly same case as they appear in entity.

因为实体具有名为newsId的持久属性，所以该属性也应在查询中使用，而不是NEWSID:

Because entity have persistent attribute named newsId, that should also be used in query instead of NEWSID:

select c FROM News c WHERE c.newsId = :id

这篇关于JPQL:状态字段路径无法解析为有效类型的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！